Method and apparatus for the conversion of starch to dextrine and the like



E K T. L E H T- 9 S D2 w mw L L W9 .I. T. H ma DI \w\ C. DMW N. wn. HF m METHOD AND APPARATUS EOE THE CONVERSION 0E sTAEo Jan. 17, 1933. N C, pHlLLlps 1,894,570

METHOD AND APPARATUS FOR THE CONVERSION OF STARCH TO DEXTRINE AND THE LIKE Filed Dec. 9. 1929 4 Sheets-Sheet 2 l O G 444 fnveno".

,MMP/ULP Jan. 17, N C. PHlLLlPS METHOD AND APPARATUS FOR THE CONVERSION OF STARCH TO DEXTRINE AND THE LIKE Filed Dec. 9, 1929 4 Sheets-Sheet 5 LL., 32 D* 445 Jan. 17, 1933. N. c. PHILLIPS 1,894,570

METHOD AND APPARATUS FOR THE CONVERSION OF STARCH TO DEXTRINE AND THE LIKE Filed Deo. 9, 1929 4 Sheets-Sheet 4 /z /29 Aaa Il I '1:0112 l: :as: o G o o o o o o o o o o Q o o o o o G o o o G o @w o e o o G o o o o o ffy/, Q o o o o o o o o o 0 o o O o o o o o o YZZ/ o o G o o o o o o o :1 :LA: :z ::v e i: :t :l e: :l

/30 ,2 y /30 /aa LAI ammi P/Llw, #V w1 NATHAN CARLETON PHILLIPS, OF GLOUGESTER,

y Patented Jan. 17, 1933 CEMENT COMPANYOF GLOUCESTER, MASSACHUSETTS, A CORPORATION OF MASSA- CHU SETTS METHOD AND APPABATUSKFOB THE CONVERSION OF BTARCH T0 DEXTRINE AND THE Application led December 9,1929. Serial No. 412,614."

This inventionconsists of a machine and method by which starch may be converted into dextrine andfwhich is adapted also for the treatment of partially converted starch and similar materials to derivatives.

For many yearsidextrine'has beenlmade commercially by impregnating starch powder with acid or other chemical material or materials and subjecting large lots in powder form to heat under agitation for many hours. By my invention, starch impregnated as heretoforeis fed` as a powder onto a moving belt in a uniform layer, preferably. thin, and carried through a heating chamber, preferably sectionalized, in which it is subjected to a predetermined, controlled heat by which it is dried (if not already dry), converted to dextrine and' cooled and then dropped intoa hopper dextrinized as completely as desired.

Uniformityof product is fof the utmost importance in adhesives as envelepe and boxmaking machines are adjusted to operate according to the character of the adhesives. A variation between lots of adhesives supplied to a machine may render the machine inoperative or require a ditticultreadjustment of its i vparte by experts with serious loss of produc- "tion. It is also important to produce a product having the characteristics best suited for the work to be done and not containing waste material.

Under existing systems it is very diicult to secure a sufficiently uniform product to satisfy users. Also, the product usually contains a substantial proportion of over or under'- dextrinized material.

It is uncertain just what happens in the dextriniaation ofl starch but the molecule is very complicated and a slight dierence in the treatment of the starch results in` substantially dilferent products.

With the apparatus hitherto vused the powdered starch is treated in large lots and,

as starch powder is a very poor conductor of heat, it is impossible thatv the diierent granules shall receive the same heatl for the same length of time. -I believe this to be a lfactor in the variation between different batches and different parts of the same batch.

ture but are polymeric. produce various starch lmachines occupying the same space and It may well be that starch grains which do not receive identical treatment in dextrinization do not have the same molecular struc- However this may be, I have foundthat to secure uniformity of product. in lots made at different times every granule of a lot substantially equal treatment of each granule is required. By my apparatus and method each granule receives substantially identical treatment as each cross section of material on the belt receives exactly the same heat at the saine relative time in its progress through the machine. Many features of my machine cooperate to produce this result as willappear from the following specification.

In consequences. very uniform product is obtained bothas to vindividua/l grams of the product and thecharacteristics of each shipment.

By myl invention, charged continuously powder in less than dextrine may be disfrom the machine as a ten minutes,` from the time the impregnated starch is fedonto the belt conveyor and the total product of one of my machines far exceeds that of existing having the same cost; and the operating expense per pound of product is less. e

Furthermore, widely dilferent products may be produced and duplicated by a variation of the materials and amounts thereof used and the conditions 4underwhich dextrinization takes place.

In the following specication, I have described a machine embodying m invention whichv is adapted to 'make a wide range of adhesives quickly and cheaply.

Fig. 1 is aside elevation of the apparatus used for carrying out the invention.

Fig. 2 is a fragmentary yfront elevation oAf Fig. 3 is a section taken along line 3--3 of Fig. -2 and illustrating thev arch-breaking MASSACHUSETTS, ASSIGNOR T0 RUSSIA and like dextrinization of msy 'the hopper taken along line 2 2 of Fig. A1.

a gears and speed-reducing niechan' porting oven gri Fig. l1 is a sid W Fig. 12 is sect"r K the drying ovens talren long belt.

Fig. 13 is a detail L tensioning means oi the Fig. 14 is a detail elevtion conveyor belt.

I will describe my machine as used in manufacture of dextrine 'roin\tapioca iiour...r

By my method twelve hundred pounds of? tapioca flour as l sold containing perhaps twelve per cent of water ic n rst impregnated with twenty-live ounces oi ydrochloric acid by weight mixed with one hundred ounces of water supplied to the flour under pressure as a mist in a manner well known and therefore not described or shown in the drawings in detail. The Hour may be placed in a mixmg device where it is kept in motion by powerful agitation or otherwise during the mixing. For the best results, the acid must be distributed equally throughout the mixture.

The foregoing material impregnatedl as aforesaid makes a good dextrine for many purposes but those skilled in the art use many different starches and mix the starch with many other materials and proportions `ac cording to the product desired and my ma-k chine is adapted to the dextrinization of all such materials which are in condition to be driedl on a belt.

The tapioca flour after being impregnated with hydrochloric acid -as above described is still an apparently dry powder and in that state is poured into a hopper, which hopper is refilled from time to time as it empties.

The hopper discharges through a narrow slot onto a horizontal travelling belt. A roller which is adjustable for height above the belt is located adjacent the discharge openin of the hopper to maintain a uniform layer o starch on the belt. The belt with the starch layer thereon passes into and through a treatin chamber preferably consisting of a plura ity oflovens where the starch is converted into dextrine and thence passes into a cooling chamber which prevents `any further reaction in the material.

charge of starch is introduced into a mixer 20 The converted product- L thence falls from the belt into a suitable jrecetacle.- l

eferring specifically to the drawings, a

located on an upper floor of the factory and compa the amount of starch that -he acidiiied starch remains a powder. Quanti ties of aeidiied starch are transferred from timeto time from the mixer into a hopper 28 of the converting apparatus, from which hopper starch is delivered as a continuous sheet or layer onto a horizontal, continuously moving, conveyor belt 30- located beneath the hoppen The conveyor belt 30 is endless and passes over an idler pulley 32 close to the hopper and over a driving pulley' 84; at the discharge end of the machine. The belt is preferably composed of thin sheet metal as steel and is ot considerable length. The length of the belt is determined lby thelength of the time the material must remain' on it and its speed and should be long enough to provide the longest treatment required by any material made on it. In the present instance, the length of the upper or material-supporting pass of the belt is approximately fifty feet long. The belt is approximately two feet wide.

The hopper has converging front and rear walls 36 and 38, respectively, and parallel upstanding side walls 40 which provide immediately above the belt a discharge orifice through which the material within the hopper is deposited upon the belt. The oriiice is elongated transversely of the belt and is terminated at its opposite endsv within the opposite side edges of the belt so that there are opposite marginal portions of the belt that are not occupied by the material. A plurality of rollers 42, see Figs. 2, 4: and 6, are located immediately under the orifice and provide supporting means for the movingbelt which prevents the buckling of thebelt due to the weight of material in the hopper on the belt. The supporting rollers are journalled in brackets 46 which are secured to longitudinally extended side bars 48 of the frame of the machine and are located under the supporting brackets 50 which are connected with the opposite side walls 40 of the hopper and which serve to support it in elevated position above the belt. The rear and front walls 38 and 36 of the hopper, respectively, are terminated a substantial distance fabove the top pass of the conveyor belt. The "space between said belt and the rear wall is occupied and closed by a roller 52 which is journalled in blocks 54- that are vertically slidable in tracks 56 carried by the two side starch from the hopper over the belt.

walls of the hopper. Screws 58 bear upon said blocks to hold the roller in rolling engagement with the belt. A scraperv or doctor is secured adjustably to the rear Wall 38 of the hopper and with the roller 52 to prevent escape of the the top of the roller. The space betweenthe belt and the front wall 36 of the hopper is closed by a pressure roller 62 which is journalledat its ends in blocks 64, see especially Figs. 'i' and 8, that are vertically slidable in tracks 66 of the side walls 40 of the hopper. can be raised and lowered by means of screws 68 which are screw threaded in rearwardly extended ears 70 lof said blocks and pass through outstanding ears 72 of the side walls 40. The bearing blocks are secured in any adjusted position by clamp'ng bolts 74 which pass through elongated slots 76 in the bearing blocks and are screw threaded in the tracks 66. A scraper or doctor 78 is vertically slidably secured to the front face of the wall 86 and bears upon the top portion of the periphery of the roller 62 whereby to prevent escape of starch from the hopper thcreover and also to remove any starch particles that may adhere to the roller. The doctor is mounted to hear yieldingly upon said roller by means including lthe compression springs 80 which bear upon said doctor and are placed under a tension which can be varied by screws 82 which are screw threaded in ears 84 of the front wall 36 and *which bear upon the tops of said springs. The pressure roller 62 is so adjusted that it is spaced above the upper pass of the conveyor belt by a distance equal to the thickness of the layer of starch that is required onthe belt. Thus, only as much starch can pass out of the hopper as is determined by the height of the roller 62 above The roller is rotated positively at the peripheral speed of the belt by a chain 86 which passes over a sprocket wheel 88A fixed to said roller an'd'also passesovcr a sprocket wheel fixed to a shaft 00, Fig. 1

extended transversely of the frame of the machine'below the hopper.

The hopper preferably is provided with means to break up any arch formation of the starch that may'tend to occur therein. Said means, as here shown, includes a shaft 92 journallcd in bearing blocks 94 secured tov the side Walls 40 of the hopper and rotated by a chain 96 which passes over an idler sprocket 98 journalled in an adjustable chain-tightening bracket 100 and over a sprocket driven by the shaft 90. rl`he shaft drives a pair of hars 102, 104, which curve helically in opposite directions lengthwise of the shaft and sweep over the frontand rear walls of the hopper thereby cutting through any arch formation ofthe starch that may tend to form a bridge between said walls and, at the saine time, moves the starch in opposite directions in engagement T he blocks 64 i. abovev the orifice of the hopper whereby to distribute the starch uniformly over the belt and therebyl insure a layer of starch of unlform thickness on thebelt it emerges from the hopper.

The belt,` with the layer of starch thereon, passes from the hopper immediately to the first one of a series of three ovens 106, 108 and 110, respectively, which are arranged lengthwise of thebelt from the hopper to ward the delivery end of the apparatus. The ovens haveessentially the same construction, although they are operated at different temperatures, and but one need be described.

Referring in particular to Figs. 9 through 1 2, the oven-106 consists essentially of a boX structure which enclosesthe upper pass of the belt 30 landfhas the toppwall 112 and the depending side walls 114 composed of suitable heat-insulating material and is supported on tie rods 116 which extend transverselyv kbeneath the belt side bars 48 of the frame of the machine. A

30 andV are carried by the metal baille is located Within the oven and against the inner face of the insulating walls and consists of a metal plate 118 which overlies and is spaced above the conveyor belt and has Vdepending side walls '120 which rest upon the tie rods 116. A grid comprising a flat metal plate 122 is located beneath the belt and upon said tie rods and has a plurality of apertures 124 therein through which hot gases can pass to traverse the under face'ofthe belt. The grid is provided with upstanding side Walls 126 which have passages 128 therethrough through which the gases beneath the belt can escape. A plurality of half-round bars 130 are secured to the upper faces of said side walls 126 and form supports over which the belt moves. A gas burner consisting of 4a perforated pipe 132 is located beneath the \,grid and extends lengthwise-thereof and is connected at its opposite ends by valved pipes 134, F ig. 1, with a gas main 136 through an interposed gas regulating device 188. rlhe burner is enclosed Within a chamber consisting of metal-faced heat-insulating walls 140 one of which consists in part of a hinged door 142 which can be lowered to permit inspection of the gas flame in the oven. The heated gases pass through the perforations of the grid and into the space 144 above the grid and under the belt and thence pass transversely of the belt and over the opposite side edges thereof and upwardly and transversely inwardly toward the middle of the belt lin the space 146 above the belt and escape from the oven through a series of valved outlet pipes 148. In this way, heat is applied to the under surface of the starch layer A on the belt and also to the upper surface thereof with the result that each particle or granule of starch in the layer receives substantially the same amount of heatpat the same time and thus all CTL .A speed-changing mechanism is of a ends the ov instable Tcors cor 1Q., which are fi ciently above tie belt to permit the starch layer to pass thereunder. l The vtop wall of the oven is providei with a roller-i541 eouru nalled vertically-adjustable supportin rod l5@ and 'which is so positionedivith reu spect to the i Pr roo, s e

oper of the belt as to hold the belt against buclrling` upwardly.

rllhe three ovens are disposed in close alignment so that'tlie material as it emerges lroin one oven passes immediately into the adjacent oven receives additional ureatment. Each oven is provided with an automatic temperature control including a temu perature indicating and controlling device 158 which is responsive to the temperature within the oven and which controlsu the device 138to regulate the supply of gas to burner `to maintain the temperature at the desired value.

Conversion ot the starch to dentrine is completed within the last oven 110. rlhe inaterial from this oven passes immediately into a cooling chamber 160 'through which cold or atmospheric air is caused to circulate above and belovir the belt by pipes 182 through which airis forced by a blower 16e. rIlhe temperature of the derrtrine is immediately lowered in the cooling chamber so that further conversion thereof is arrested. ihe dentrine on the belt 4lallsod the belt into a suitable receptacle as the belt passes over the driving pulley 3e. .el power driven brush 168 rotates in engagement with the under pass of the belt on the pulley 84 so as to brush oil any material that may tend to adhere to the belt. l

The power for actuating the various parte of the apparatus is obtained from an electric motor 170 which drives a shaft 172 and, through a belt 17d, the shaft 178 of a variable speed mechanism by which the speel of the conveyor belt can be adjusted tolsuit the temperatures ot ovens and the particular product that is being manufactured. The well known type and consists essentially of cones 178 which can be moved toward and away from each other on the shalt 176 and which engage the edges of Na belt-180 which belt drives cones 182 that function similarly to the cones 178 and drive the shaft 18e, see Figs.. I1 andli. The shaft 184. is connected with the shaft 186 of the driving pulley 3l of the conveyor belt by means ot suitable speed-reduction gears 188. The arch-breaking device and the layer-forming roller o the hopper are driven from the motor 170 through the variable speed mechanism'lQO which is connected with the shalt 90 so that the hopper can be operated a speed which is correlated 'with the speed of the conveyor belt.

coveyor belt is lmaintained under suitable tension by means o the idler pulley 82. To this end, the shalt 192 of said pulley is mountin bearing blocks 19d, see Fig. 18, which are slidable in tracks 196 carried by both horizontal trame bars d8. Flexible cables 198 are connected with said bloclrs and pass over a series ot sheaves 2Q() to a cross bar 202 lon cated beneath the idler pulley and carryingV a weight 204s thereby keeping the belt under tension regardless ot variations in length of said belt due to changes of temperatures.

lllach oven is heated to a predetermined dcgree which can be varied at will to suit the requirements of any particular product but the heat is preferably governed by the controlling devices mentioned which are well known in the art to maintain the oven closely at whatever' temperature has been selected. rlhe more refined the heat control is the better, but `find that three heating sections, heated by gas jets, as above described, and the cooling section cooled by air at room temperature gives me sucient control of the process to give highly satisfactory results for the conversion of starch into dextrine.

The temperatures and belt speed must be governed by the materials used and the product desired. Those skilled in the art know very 'closely the highest temperature it is safe to use for their product. with tapioca r'lour impregnated as described the heat may be adjusted to give the belt a -temperature at the' outlet of the first oven of 280 F., at the outlet of the second oven of 300' F., and at the outlet of the third oven of 320 F. rlChe 'fourth section 160 is merely for cooling the material promptly so that the material willvnot be over-converted. As above stated, lair at ordinary room temperature may be used tor cooling. j

More heat should be supplied in the irst section as the heat has to vaporizo the moisture in the material as well as raise thc tcmperature thereof. ln the second section, the dextrinization proceeds and is linished in the third section, preferably at the highest sate temperature. l have used various belt speeds. More than live foot per minute is easily obtained. The 'faster the belt the more heat must be supplied but speed is limited by the fact that the material mustnot be overheated, and heat must be enough to convert the dextrine no matter what 'the spe-ed. "lapioca starch can be dcxtrinized commercially much vmore perfectly by the above method than by any other method known to me. l

My machine may be used to treat not only impregnated material but starch which has not been impregnated and also to give a second treatment yto starch mixtures or derivatives which have already been once 'treated by my machine or otherwise.

The layer of starch on the conveyor belt l find that Y ing the sion of tapioca iioury be much more than one-eighth of an inch. There is no harm in having the starch layer thinner than this but as a thin layer reduces the output of the machine, I prefer to run the layer as thick as I can so long as I am assured that all granules of starch will receive uniform treatment so that all granules will be equally converted to dextrine. If the layer is too thick all particles of the layer will not receive the same heat treatment so that the productA will not be uniform but with a suihciently thin layer all granules will receive the same heat at the same time so that a uniformity of product, heretofore commercially unattained, is assured.

It is obvious that if perfect uniformity of product is not required my machine may be used without all of the desirable features here explained. For instance, the layer may e too thick for a perfect product and yet the machine will produce a large output of dextrine sufficiently ood for many purposes. Furthermore, those -s illed in the art, followingv the principles herein disclosed, may choose to use thinner layers of material, more exact heat control, or othervariations to produce a more perfect product.

TheV term thin used in the claims to limit the thickness' of the starch layer is used to mean a layer of the order described in this specification and variable as therein explained.

I claim v:z j

l. The method of lconverting starch in powder form into dextrine which consists in forming the starch containing material to be converted into a uniform thin layer, carrying the layer forward at uniform speed through a heat controlled atmosphere without v'agitation or disturbance of formation, subjecting each cross section 'of the material to the same heat at the same relative time in its treatment, and predeterminingand adjusting theheat supplied to dextrmize the material tothe desired amount.

2. rIhe method of converting starch t in powder form into dextrine which consists in orming the starch containing material 'to be converted into a uniform thin layer, carrylayer forward at uniform speed through a heat eontrlled atmosphere without agitation or disturbance of formation, subjecting each cross section of the material from top and bottom to the same heat at the same relative time in its treatment, and predetermining and adjusting the heat supplied to dextrinize the material tothe desired amount. 0

3. The method of converting starch 1n powder form into dextrine which consists in forming the starch containing material to be converted into a uniform thin layer, carrying/the layer forward at uniform speed to dextrine should not lmaterial while rying the layer forward through a heat controlled atmosphere without agitation or disturbance of formation, subjecting each cross sectioneof the material to the same heat at the same relative time in its treatment, predetermining and adjusting the heatsupplied to' deXtrinize the material to the desired amount, and coolingcthe still progressing at uniform speed in said layer form.

4. The method of converting starch in powder form into dextrine which consists in forming the starch containing material to be converted into a uniform thin layer, carryingA the layer forward at uniform speed through a heat controlled atmosphere without agitation or disturbance of formation;

subjecting` each cross section of the material from top and bottom to the same heat at determining and adjusting the heat supplied to .dextrinize the material to the desired amount, and cooling the material while still progressing at uniform speed in said layer form.

dextrinize the material to the desired amount.

6. 'Ihe method of 'converting starch in owder form into dextrine which consists in forming the starch containing material to be converted into a uniform thin layer, carat uniform speed through a heat controlled atmosphere without agitation or' disturbance of formation, subjecting each cross section of the material from top and bottom to the same heat at the same.

relative time in its treatment but varying the heat by predetermined amounts at different stages of the progress of the material, and predetermining and adjusting the heat supplied to dextrinize the material to the desired amount.

7. The method of converting starchl in powder form into dextrine which consists in g forming the starch containing material to be converted into a uniform vthincompacted layer, carrying the layer `forward at uniform `the same relative time in its treatment, prethrough a heat controlled lid speed through a heat controlled atmosphere without agitation or disturbance of formation, subjecting each cross section of the material to the same heat at the same relative time in its treatment, and predetermining and adjusting the heat supplied to dextrinize the material to the desired amount.,

8. The method of converting starch in stamt or d cross section of iisg@ at the same, Tela Predetermm plied to dextr1nze m 

